What is the India-Pakistan conflict at sea about?

1. At a Glance

• A rare naval collision between an Indian Navy destroyer (INS Kolkata) and a Pakistan Navy patrol vessel (PNS Hunain) occurred in the North Arabian Sea on 15 September 2026 [4].
• Central to the dispute is Article 10 of the 1991 India-Pakistan Agreement, a confidence-building measure (CBM) mandating a 3-nautical-mile separation between naval vessels [4][5].
• For UPSC: tests knowledge of India-Pakistan CBMs, naval law of the sea, and current bilateral friction — relevant to GS-II (bilateral relations) and GS-III (internal/external security).
• Illustrates how legacy bilateral agreements (pre-dating even the Lahore Declaration) remain operative flashpoints in India-Pakistan maritime relations.

2. Why in the News

• On 15 September 2026, Pakistan Navy vessel PNS Hunain collided with Indian Navy warship INS Kolkata roughly 220 km east of Oman in the North Arabian Sea, allegedly after Hunain executed a dangerous high-speed overtaking manoeuvre [1][4].
• India summoned Pakistan's Charge d'Affaires on 16 September 2026 and lodged a formal protest, citing violation of Article 10 of the 1991 Agreement [1][4].
• Pakistan rejected India's version; India in turn rejected Pakistan's counter-claims on 18 September 2026, calling them "usual prevarication" [1].

3. Background & Evolution

• April 1991: India and Pakistan signed the "Agreement on Advance Notice on Military Exercises, Manoeuvres and Troops Movements" — a CBM to reduce risk of misinterpreted military activity [2][5].
• The agreement covers advance notification of large-scale exercises/troop movements and, under Article 10, mandates minimum separation distances for naval vessels operating in international waters [2][5].
• This sits alongside other India-Pakistan CBMs (e.g., 1988 Prohibition of Attack against Nuclear Installations Agreement, 1991 Agreement on Prevention of Air Space Violations) forming the post-1971 bilateral risk-reduction architecture.
• The 15 September 2026 incident is described as testing this three-decade-old pact's continued relevance under current tensions [3].

4. Core Static Facts

5. Multi-Dimensional Analysis

Geopolitical / Strategic

• Adds to an already tense India-Pakistan security relationship; naval incidents carry escalation risk distinct from land-border friction [1][4].
• Tests credibility of 1991-era CBMs designed for a very different threat environment (pre-nuclear-tests, pre-Kargil) [3][5].

Legal / Constitutional

• Dispute centres on treaty interpretation — whether Article 10's 3-nm rule was breached, and by which side's manoeuvre [2][4].
• No third-party/international arbitration mechanism exists under this bilateral pact; recourse is diplomatic protest only [1].

Administrative

• Response routed through Ministry of External Affairs (summoning of envoy) and Indian Navy (operational account), showing civil-military coordination in crisis messaging [1][4].

Historical

• Continues a pattern of India-Pakistan bilateral CBMs from the 1980s-90s (nuclear installations pact 1988, air-space violations pact 1991, this agreement 1991) meant to institutionalise restraint short of full normalization.

6. Recent Developments (last 12-18 months)

• 15 September 2026: Collision between INS Kolkata and PNS Hunain in North Arabian Sea [1][4].
• 16 September 2026: India summons Pakistan's Charge d'Affaires; formal protest lodged citing Article 10 violation [1][4].
• 18 September 2026: India publicly rejects Pakistan's counter-narrative, terming it "usual prevarication" [1].

7. Prelims Hooks

• The 1991 India-Pakistan Agreement on Advance Notice on Military Exercises, Manoeuvres and Troops Movements was signed in April 1991 [2][5].
• Article 10 of this agreement mandates naval vessels stay at least 3 nautical miles apart in international waters [2][5].
• 3 nautical miles ≈ 5.56 km [2].
• INS Kolkata is the lead ship of the Project 15A "Kolkata-class" guided-missile destroyers (Excerpt).
• INS Kolkata was built by Mazagon Dock Shipbuilders, Mumbai (Excerpt).
• INS Kolkata was commissioned into the Indian Navy in August 2014 (Excerpt).
• INS Kolkata has full-load displacement of about 7,400 tonnes and top speed of 30 knots (Excerpt).
• PNS Hunain is an offshore patrol vessel of the Pakistan Navy [1].
• The September 2026 collision occurred roughly 220 km east of Oman in the North Arabian Sea [1].
• India's diplomatic response involved summoning Pakistan's Charge d'Affaires (not the High Commissioner) [1][4].
• Damage outcome: INS Kolkata unharmed and remained at sea; PNS Hunain heavily damaged and returned to harbour [1].
• The 1991 Agreement is distinct from the 1991 Agreement on Prevention of Air Space Violations — do not conflate the two pacts.

8. Why Nobody Can Prove Who Was at Fault

• The pact has a rule but no referee
• Article 10 says ships must stay 3 nautical miles apart. It does not say who checks whether that happened [2][5].
• So each navy writes its own account. India says PNS Hunain made a dangerous overtaking move; Pakistan says the opposite; India then called Pakistan's version "usual prevarication" [1][7].

• Both sides are judge in their own case. The fact never gets settled.

• The only tool India has is a protest

• There is no arbitration, no joint inquiry, no third party under this pact [1].
• India's response was to summon Pakistan's Charge d'Affaires — a day after the collision [1][4].

• A diplomatic protest cannot stop a manoeuvre that is already over. It only records anger.

• This is not the first time the same clause was argued over

• The same 3-nautical-mile rule was in question in a similar episode about 15 years earlier [3].

• A rule that is disputed twice with no result in between is a rule nobody enforces.

• For the exam: the useful sentence is not "the CBM failed" but "the CBM has no verification machinery", which is a different and sharper point.

9. What Article 10 Does Not Say

• It is a distance rule, not a driving rule
• Article 10 only fixes how far apart warships must stay in international waters [2][5].
• It does not say which ship must give way when two ships approach, or how an overtaking ship must pass.
• The actual "rules of the road" at sea come from a separate 1972 international convention on preventing collisions at sea, made under the IMO [8].

• So the two countries are arguing under a pact that was never written to decide a collision.

• The pact was designed for planned events, not daily patrols

• Its main job is advance notice of large exercises, manoeuvres and troop movements, and keeping big exercises away from the other side, on land, at sea and in the air [2][5][7].
• An exercise is announced in advance. A routine patrol is not.
• The 15 September 2026 meeting was two ships on ordinary deployment — exactly the situation the pact gives least guidance on [1][7].

10. Why the Two Navies Keep Meeting in the Same Water

• Both navies now live in the North Arabian Sea, not visit it
• The Indian Navy keeps warships "mission deployed" in the Arabian Sea for long stretches, for anti-piracy and maritime security work — for example responding to a hijacking there [9].
• Mission deployment means ships sit on station for weeks, not sail past.

• Pakistan's coast and its main ports open onto the same sea.

• More time at sea means more chances to be within 3 miles

• The collision happened about 220 km east of Oman — busy water near Gulf shipping routes, not an empty corner [1].
• A rule written in 1991, when navies went to sea for short exercises, now has to cover near-permanent presence.
• This is why such incidents are likely to repeat, whatever either side says after this one.

11. The Case That the 1991 Pact Actually Worked

• The strongest argument against the pact: it did not stop the collision, it cannot name the guilty ship, and both navies simply denied each other's account [1][7]. On its own stated purpose — keeping warships 3 miles apart — it plainly failed on 15 September 2026 [2][4].
• But look at what did not happen
• Two armed warships of hostile neighbours touched at sea, and nobody fired [1][4].
• The dispute moved straight to the Ministry of External Affairs and a summons, not to the guns [1][4].

• Because a written rule existed, India had something to accuse Pakistan of breaking. Without it, the same event is just an insult with no agreed standard.

• Honest conclusion for an answer

• CBMs of this type do not prevent incidents. They convert incidents into paperwork.
• That is a smaller claim than "strategic stability", but it is the claim the evidence supports.

12. What Would Cut the Risk, and Who Has to Do It

• The two navies need to talk to each other directly, not through diplomats
• Today the chain is: collision at sea, then next day the Ministry of External Affairs summons a diplomat in Delhi [1][4].
• That takes a day. A ship closing at 30 knots takes minutes [6].

• A direct navy-to-navy channel, used while the ships are still in sight of each other, is the only thing that works on that timescale.

• Extend the pact's own advance-notice idea to routine deployments

• The 1991 agreement already requires advance notice of big exercises and keeping them away from the other side [2][5][7].
• The same logic, applied to declaring patrol areas in the North Arabian Sea, would stop two ships arriving in the same water by surprise.

• This needs no new treaty — only an added protocol to an agreement both sides still accept as binding [2].

• Write down the rules of the road, not just the distance

• India and Pakistan should agree that the 1972 collision-prevention rules apply between their warships too, so overtaking and give-way duties are settled in advance [8].
• Then a future incident has a test to apply, instead of two press statements [1][7].

13. Anchors for Answers

• Data: Article 10 minimum separation for warships — 3 nautical miles (about 5.56 km) in international waters [2][5]
• Data: Collision of 15 September 2026, about 220 km east of Oman; India protested on 16 September and rejected Pakistan's version on 18 September [1][4][7]
• Law/Treaty: 1991 Agreement on Advance Notice on Military Exercises, Manoeuvres and Troops Movements — Article 10; sister CBMs of 1988 (nuclear installations) and 1991 (air space violations) [2][5]
• Comparison: Convention on the International Regulations for Preventing Collisions at Sea, 1972 (IMO) — a multilateral rulebook that fixes give-way and overtaking duties, which the bilateral pact does not [8]
• Scheme/Practice: Indian Navy "mission deployed" platforms kept on station in the Arabian Sea for anti-piracy and maritime security response [9]
• Precedent: The same 3-nautical-mile clause was disputed in a comparable episode roughly 15 years earlier, with no settled outcome [3]

14. Mains Relevance

• GS-II: India and its neighbourhood — India-Pakistan relations, bilateral agreements/CBMs.
• GS-III: Internal and external security challenges — role of external state actors, security forces & agencies.
• Possible question stems: 1. Discuss the significance of the 1991 India-Pakistan Agreement on Advance Notice on Military Exercises in maintaining strategic stability. Examine its relevance in light of recent naval incidents. (GS-II) 2. Bilateral confidence-building measures between India and Pakistan have often failed to prevent escalation. Critically evaluate with recent examples. (GS-II) 3. Analyse the challenges of maritime security cooperation between adversarial neighbours in the absence of binding dispute-resolution mechanisms. (GS-III)

15. Related Topics to Study Next

• Lahore Declaration (1999) — subsequent India-Pakistan CBM framework, complements the 1991 pact.
• 1988 Agreement on Prohibition of Attack against Nuclear Installations — sister CBM in the same bilateral series.
• 1991 Agreement on Prevention of Air Space Violations — parallel domain-specific pact, often confused with the military-exercises agreement.
• Project 15A / 15B Destroyers (Indian Navy) — shipbuilding and indigenisation angle (Atmanirbhar Bharat in defence).
• UNCLOS and Freedom of Navigation — international law governing conduct in international waters.
• Indus Waters Treaty and post-Pahalgam bilateral tensions — broader context of strained India-Pakistan ties in 2025-26.
• Indian Ocean Region (IOR) maritime security architecture — QUAD, Indo-Pacific strategy relevance.

16. Common Errors / Trap Areas

• Confusing the 1991 Agreement on Advance Notice on Military Exercises (Article 10 = naval separation) with the separate 1991 Agreement on Prevention of Air Space Violations.
• Assuming the incident occurred in territorial waters — it occurred in international waters in the North Arabian Sea.
• Mixing up which vessel was damaged — PNS Hunain (Pakistani) was damaged, not INS Kolkata.
• Attributing India's diplomatic response to the High Commissioner — it was the Charge d'Affaires who was summoned.
• Misdating INS Kolkata's commissioning — it is 2014, not the year of the 2026 incident.